Software development is a young profession, and we are still learning the techniques and building the tools to do it effectively. I've been involved in this activity for over three decades and in the last two I've been writing on this website about patterns and practices that make it easier to build useful software. The site began as a place to put my own writing, but I also use it to publish articles by my colleagues.
In 2000, I joined Thoughtworks, where my role is to learn about the techniques that we've learned to deliver software for our clients, and pass these techniques on to the wider software industry. As this site has developed into a respected platform on software development, I've edited and published articles by my colleagues, both ThoughtWorkers and others, to help useful writing reach a wider audience.
photo: Christopher Ferguson
Martin Fowler
If there's a theme that runs through my work and writing on this site, it's the interplay between the shift towards agile thinking and the technical patterns and practices that make agile software development practical. While specifics of technology change rapidly in our profession, fundamental practices and patterns are more stable. So writing about these allows me to have articles on this site that are several years old but still as relevant as when they were written.
As software becomes more critical to modern business, software needs to be able to react quickly to changes, allowing new features to be be conceived, developed and put into production rapidly. The techniques of agile software development began in the 1990s and became steadily more popular in the last decade. They focus on a flexible approach to planning, which allows software products to change direction as the users' needs change and as product managers learn more about how to make their users effective. While widely accepted now, agile approaches are not easy, requiring significant skills for a team, but more importantly a culture of open collaboration both within the team and with a team's partners.
This need to respond fluently to changes has an important impact upon the architecture of a software system. The software needs to be built in such a way that it is able to adapt to unexpected changes in features. One of the most important ways to do this is to write clear code, making it easy to understand what the program is supposed to do. This code should be divided into modules which allow developers to understand only the parts of the system they need to make a change. This production code should be supported with automated tests that can detect any errors made when making a change while providing examples of how internal structures are used. Large and complex software efforts may find the microservices architectural style helps teams deploy software with less entangling dependencies.
Creating software that has a good architecture isn't something that can be done first time. Like good prose, it needs regular revisions as programmers learn more about what the product needs to do and how best to design the product to achieve its goals. Refactoring is an essential technique to allow a program to be changed safely. It consists of making small changes that don't alter the observable behavior of the software. By combining lots of small changes, developers can revise the software's structure supporting significant modifications that weren't planned when the system was first conceived.
Software that runs only on a developer's machine isn't providing value to the customers of the software. Traditionally releasing software has been a long and complicated process, one that hinders the need to evolve software quickly. Continuous Delivery uses automation and collaborative workflows to remove this bottleneck, allowing teams to release software as often as the customers demand. For Continuous Delivery to be possible, we need to build in a solid foundation of Testing, with a range of automated tests that can give us confidence that our changes haven't introduced any bugs. This leads us to integrate testing into programming, which can act to improve our architecture.
Cape Cod, MA (2017)
There are many kinds of software out there, the kind I'm primarily engaged is Enterprise Applications. One of the enduring problems we need to tackle in this world is data management. The aspects of data managment I've focused on here are how to migrate data stores as their applications respond to changing needs, coping with different contexts across a large enterprise, the role of NoSQL databases, and the broader issues of coping with data that is both Big and Messy.
A common problem in complex software systems is how to capture complicated domain logic in a way that programmers can both easily manipulate and also easily communicate to domain experts. Domain-Specific Languages (DSLs) create a custom language for a particular problem, either with custom parsers or by conventions within a host language.
I've written seven books on software development, including Refactoring, Patterns of Enterprise Application Architecture, and UML Distilled. I'm also the editor of a signature series for Addison-Wesley that includes five jolt award winners.
I'm often asked to give talks at conferences, from which I've inferred that I'm a pretty good speaker - which is ironic since I really hate giving talks. You can form your own opinion of my talks by watching videos of some my conference talks.
I've long been a fan of board games, I enjoy a game that fully occupies my mind, clearing out all the serious thoughts for a bit, while enjoying the company of good friends. Modern board games saw dramatic improvement in the 1990's with the rise of Eurogames, and I expect many people would be surprised if they haven't tried any of this new generation. I also appear regularly on Heavy Cardboard.
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Tue 19 Sep 2023 08:57 BST
How is code generation with GenAI different from more "traditional" code generators? The newest memo in Birgitta Böckeler's explorations of GenAI talks about abstraction levels in software engineering, and on which levels GenAI sits in the translation of our thoughts into zeros and ones.
Wed 23 Aug 2023 10:37
Many software teams create services exposed as APIs, designed to be consumed by other software and thus without any user-interface. Such services are hard to demonstrate, as they effectively just dump pages of JSON. A demo front-end is a simple user-interface just used to manipulate such an API. Matteo Vaccari describes how and why to build one - showing its usefulness both in explaining the API's capabilities to stakeholders and to help client developers explore how to interact with the API.
Tue 22 Aug 2023 10:21
Here is a new article in the bottlenecks of scaleups series, looking at resilience and observability. Startups tend to only address resilience when their systems are already down, often taking a very reactive approach. For a scaleup, excessive system downtime represents a significant bottleneck to the organization, both from the effort expended on restoring function and also from the impact of customer dissatisfaction. Punit Lad and Carl Nygard explain that to move past this, resilience needs to be built into the business objectives, which will influence the architecture, design, product management, and even governance of business systems.
Mon 14 Aug 2023 14:58
We are saddened today to learn of the passing of Stefan Tilkov. We’ve met Stefan several times at workshops and conferences and always enjoyed his good company and insightful views. He advocated many of the things that we and our colleagues support - and as well as skillfully explaining these ideas, he also backed them up with concrete experience from his work. We shall really miss his wise contributions online, and regret that we won’t get the chance to chat with him again. We offer our condolences to his family, friends, and colleagues at INNOQ.
Tue 08 Aug 2023 16:05
My colleague Sarah Taraporewalla describes an approach to building technology strategy that challenges the convention. It starts by identifying the overall strategic directions that the organization is considering, and using common aspects of these directions to indicate the investigations needed for the organization to understand the technology implications raised by that strategic change. This first installment looks at two of these directions: expanding the business by creating complementary products, and expanding the business into new markets and regions.
Mon 31 Jul 2023 09:30
As startups begin to grow rapidly, they often find that early decisions that helped them find a product/market fit lead to excessive costs once traffic increases. These costs can threaten a scaleup's ability to grow. Sofia Tania and Stefania Stefansdottir have worked with many scaleups in this predicament and share their approach to understanding and reducing these costs.